This invention relates to the manufacture of polymeric contact lens structures wherein the structure is produced with an identifying means comprising short segments of elongated strand, rod or fiber indicia molded into the structure during manufacture.
This invention further relates to contact lens manufacture wherein a lens is produced having a gradation or variation in physical properties from the central portion to the peripheral skirt portion of the lens and has means for identifying the lens incorporated into the lens during manufacture.
This invention also relates in one variant form thereof to a contact lens having a relatively harder central portion and a softer hydrophilic peripheral skirt portion with identifying means incorporated directly into the lens.
In many instances the production, distribution and use of contact lenses and other types of polymeric structures will be improved by having a clearly distinguishable and permanent identifying means incorporated into the structure. Contact lenses marketed heretofore have not contained an identification means permanently located within the lens thus making identification of and evaluation of the lens difficult.
Soft lenses heretofore known are generally prescribed with companion lenses which are virtually indistinguishable from each other to the wearer. This presents the potential problems that a lens prescribed for the left eye may inadvertently be placed in the right eye and vice versa.
U.S. Pat. No. 3,034,403 shows the use of a dissimilar zone in the center of a contact lens for the sole purpose of effecting the light transmissibility of the lens. Use of such a dissimilar zone in a contact lens for identification purposes was not disclosed therein. Distinguishing between two lenses both having a dissimilar zone is often impracticable; this indistinguishability precludes the conclusion that such a dissimilar zone necessarily performs an identification function similar to the current invention.